It is generally thought that catecholamines are involved in the control of reproduction, but there is presently little direct and consistent biochemical evidence for this notion. Preliminary experiments in the rat indicate that regulation of the responsiveness of catecholamine receptors may be an important control mechanism in reproductive function. We propose to study this possibility further by examining the response to agonists under different reproductive states using both cAMP accumulation and LHRH release as indicators of receptor activity. For work with rat, a technique was developed for studying cAMP in individual nuclei from brain slices incubated in vitro. For rhesus monkey, intraventricular injections of agonists will be followed by collection of CSF for assay. In addition to their significance for an understanding of reproductive function, these experiments will provide, for the first time, biochemical information on catecholamine receptors at the level of individual nuclei, especially in hypothalamus, and will bear on the feasibility of utilizing CSF cAMP for studies of receptors in primates.